1. Field of the Invention
This invention relates to an alignment means and more particularly to an alignment means adapted to align vehicle axles and wheels. Specifically, the instant invention relates to an alignment means employing a fixed reference located relative to the frame of a vehicle and a means for establishing the centerline of the axle of the vehicle whereby the distance between the fixed reference point and the centerline of the axle may be measured in order to determine alignment of the axle with respect to the frame. In addition, the camber of the wheels may be determined by using level means.
2. Description of the Prior Art
Alignment means for aligning vehicle wheels are well-known in the art as evidenced by British Pat. No. 778,838 and numerous advertisements found in trade publications such as the Modern Tire Dealer at Volume 63, Number 7, June of 1982 at page 3; Volume 63, Number 4, April of 1982 at page 13; Volume 62, Number 2, February of 1981 at page 16; Volume 63, Number 9, August of 1982 at page 31; Volume 63, Number 7, June of 1982 at page 44; Volume 62, Number 4, April of 1981 at page 34; Volume 63, Number 11, September of 1982 at page 10; Volume 62, Number 8, July of 1981 at page 6; Volume 63, Number 8, July of 1982 at page 43.
These prior art devices typically utilize a wheel clamp affixed to the wheel of a vehicle, said wheel clamp having sensors which are utilized to determine the orientation of the wheel and thus the alignment of the wheel/tire combination.
The apparatus employed by the prior art is typically intended to be used in a truck repair facility and conventionally employs rather sophisticated equipment and specialized devices in order to align vehicle wheels.
It has been recognized, as shown in the Modern Tire Dealer, Volume 63, Number 7, June of 1982 at page 31, that alignment of the drive axles of trucks with respect to their frame members is extremely important. Rear axle misalignment can create side forces resulting in uneven wear on the steering axle tires as well as drive axle tires.
The two most common faults are drive axles that are not perpendicular to the chassis centerline and drive axles that are not parallel to each other. In either case, drive axle misalignment will not only cause scuffing of the rear tires, but will also put a steady side force on both front tires leading to rapid wear of the front tires. Because this front tire wear resembles toe wear, it is often difficult to pinpoint the actual problem. A typical means for aligning the axles of a truck is found in the Modern Tire Dealer, Volume 62, Number 7, June of 1981 at page 55. Generally, the loaded truck is parked on level ground, preferably using the hand brake or trailer brakes to stop so ride heights will be typical. A plump bob string is then taped to the fender of the truck in order that the plumb line is centered over the hub when viewed from the side. A tape measure is then used to measure the distance from the string to the flange at the top of the wheel and is again used to measure the distance from the string to the flange at the bottom of the wheel. The difference in measurements between the measurement at the top of the flange and the measurement at the bottom of the flange provides an indication of the camber of the wheel.
Axle alignment may be checked in a somewhat similar manner by parking the loaded truck on a flat surface. A plumb line is then dropped from the point where each end of each axle meets its spring. A comparable point is used at each axle spring junction. The plumb points are then marked on the ground and the truck is moved. The distance between the points is then measured to determine axle alignment.
It has been found that this method of determining truck alignment is somewhat time consuming and yields results which are not sufficiently accurate. The instant invention is intended to remedy these problems by providing a means for quickly determining the alignment of a vehicle to a reasonable degree of accuracy.